In the semiconductor industry, systems for transporting wafers between process locations in a sputtering system are well known. Typically circular silicon wafers of various diameters are moved between positions at which metallic coatings are sputtered onto the wafer or at which etching occurs. This process takes place in a vacuum chamber in order to eliminate contamination of the wafer surface. The goal of all such transport systems is to move the wafer from one process location to another.
The transport system within the vacuum chamber can include shuttles to move wafers horizontally and elevators to move wafers vertically. The motion of such shuttles and elevators must be coordinated in order to deliver the wafer from shuttle to elevator or elevator to shuttle. In order to increase the efficiency and volume of output of wafer processing systems, sputtering systems are often designed to process multiple wafers at the same time. Such multiple wafer systems often require moving a shuttle past an internal station where a wafer is being processed without interferring.
Shuttles which pass wafers along a track in a horizontal position are often used with elevators which lift the wafer from the shuttle through a hole in the center of the shuttle. These transport systems have the disadvantage that the shuttle cannot be moved while the elevator is up. Only after the elevator has returned the wafer to the shuttle and withdrawn from the center of the shuttle can the shuttle move.
The objects of this invention then are to describe an elevator and shuttle suitable for lifting a workpiece from a shuttle while permitting the shuttle to move while the elevator is in the up position, to make such an apparatus simple, rugged and inexpensive to manufacture, and to provide firm support for the wafer at all times.